Mechanical fluid connections for joining pliable hoses such as a flexible elastomeric or polymeric fluid conveying hose to a pressurized fluid system have traditionally consisted of a barbed hose nipple that is inserted into a pliable hose. The barbs “bite” into the inside layer of the hose and function to retain the hose in position on the hose nipple. In some installations, a clamp such as a band clamp or a wire twist clamp is installed over the hose to apply additional clamping force on the outside of the hose to increase the retention of the hose on the barbs
Prior art clamps such as band clamps or single or double wire spring clamps have been used to apply additional clamping force on the outside of the hose. For example, U.S. Pat. No. 3,805,337 to Branstetter discloses a single wire self-tightening spring hose clamp that is commonly used to apply a clamping force on a pliable hose to retain it on a barbed fitting. This is shown as clamp 10 in FIGS. 1-3 of the '337 patent.
U.S. Pat. No. 3,333,871 to Abbiati et al, discloses a dual wire self-tightening spring hose clamp that is used to apply a clamping force to a pliable hose to assist in retaining the hose in place on a barbed hose nipple of a hose coupling fitting. This spring hose clamp is shown in FIG. 2 as clamp 35 in the '871 patent.
U.S. Pat. No. 4,299,012 to Oetiker, discloses a band type hose clamp where its ends are clipped together upon assembly by extending hooks which engage apertures. The clamp can be tightened further by a bolt fastener which, upon rotation, further reduces the inside diameter of the clamp.
These clamps have proven difficult to handle in a production process because the clamps are separate pieces and their performance in some applications is suspect. Installation on the hose requires the use of a tool that can prove difficult to use in constricted environments. Also, after some period of time in service, the clamping force of the clamp degrades due to a permanent deformation under the clamp. Under high pressures, the tube or hose can experience a change in wall thickness due to axial stresses. This thinning of the wall thickness can result in a decreased clamping force on the hose when prior art clamping systems are used to apply a clamping load.